In wiper blades, the support element for the entire field swept by the wiper blade is intended to assure the most uniform possible distribution of the wiper blade contact pressure, originating in the wiper arm, against the window. By means of suitable curvature of the unloaded support element--that is, when the wiper blade is not resting on the window--the ends of the wiper strip, which in wiper blade operation is pressed completely against the window, are located by the then tensed support element toward the window, even if the radii of curvature of spherically curved vehicle windows change in every wiper blade position. That is, the curvature of the wiper blade must be somewhat greater than the greatest curvature measured in the wiping field of the window to be wiped. The support element thus replaces the complicated support bracket construction with two support elements disposed in the wiper strip of the kind used in conventional wiper blades.
The invention takes as its point of departure a known wiper blade (German Patent Disclosure DE 26 14 457), in which the connection device is integrally joined to the support element. Hence it is made of the same material as the support element. This may possibly be of secondary importance as long as the support element is made from a plastic which is therefore made by filling a suitable mold. However, if the support element is to be made of metal, then two demands directly contradict one another. On the one hand, the support element should have good spring properties, but on the other the attachments of the connection device should be easily bent by approximately 90.degree. out of the plane of the support element and fixed in that position, so that the loads occurring in operation between the wiper blade and the wiper arm can be absorbed on stop faces of these attachments. These two demands are virtually impossible to meet unless disadvantageous compromises in the choice of material are made.
In another known wiper blade (German Published, Examined Patent Disclosure DE-AS 12 47 161), the support element is provided with a connection device as a separate component. This connection device is solidly joined to the support element with the aid of rivets. The requisite bores in the support element, however, lead to an undesired, because uncontrollable, change in the support element tension, so that a satisfactory window wiping result cannot be attained.